Manufacture of cellulose compounds



Patented Jan. 10, 1928.

FREDERICK CARL NIEDERHAUSER AND HAYDEN BENJAMIN KLINE, F CLEVELAND,

OHIO.

MANUFACTURE OF CELLULOSE COMPOUNDS.

No Drawin This invention relates to the manufacture of viscose rayon products, such as filaments, threads, films and the like from wood cellulose, or from pulp containing a proportion of wood cellulose, and to a method of treatment of the viscose solution before coagulation whereby more uniform and regular products are produced, as will be more specally set out below. I

In the production of filaments and other compounds from viscose, especially in the spinning of the finer counts, and when the temperature of the viscose solution being spun is elevated-above the normal for opti mum spinning conditions, there is a tendency for a reduction in viscosity to the extent that the surface tension of the jet solution becomes such a predominating factor that the viscose solution leaves the jet ori- 2 fice in a fluctuating or discontinuous, instead of in a continuous and uniform stream, resulting in unevenness of thread as shown by variations in denier, which in general, is undesirable, and we believe due in large measare to a high surface tension in the viscose being spun.-

We therefore instituted researches on surface tension measurements in the laboratory to determine whether by the addition of some chemical product to the viscose during or after its preparation, the surface tension might be reduced to a sutlicient eiztentso that a continuous and uniform flow of viscose solution from the. jet into the coagulating bath while spinning, rather than a flow which is in part fluctuating and substantially intermittent. Our researches culminated in observations that water-soluble sulfonated non-mineral oils when used in relatively small proportions effected the result desired, and the disclosures of the same 'forms the subjectmatter of this application.

This inventionrelates to a method for the reduction of the surface tension of the spinning viscose from 15% to 25% and in some instances greater, by theintroduction into the process of viscose manufacture at any suitable point before the viscose has issued into filament form, ofrelatively small proportions'of the alkali metal salts of the a mixed acids from non-mineral oils, said non-mineral oils having been sulfonated previous to the introduction to the alkali metal and theformation of the corresponding sulfonated acid salt.

Application filed December 21, 1926. Serial No. 156,252.

Of the vegetable oils in their sulfonated form and as alkali metal salts which we have employed in aqueous solution for the reduction of surface tension of viscose solutions, may be mentioned almond, castor, corn, olive, cocoanut, colza, cottonseed, hempseed, linseed, mustard, palm, poppy, tung, nut and peanut oils; and of the animal oils ivehave used sulfonated compounds of lard, tallow, neats-foot and various fish oils. Their method of manufacture in sulfonation and neutralization of the sulfonated oil varies with the individual oil and its relative purity and forms no portion of the claims of this specification. Some of the alkali metal salts of the sulfonated acids derived from the above mentioned sources, while acting efficiently, have drawbacks such. as imparting a disagreeable odor to the finished filaments which is removable with difficulty, or on account of the relatively higher cost of the oil in the degree of purity required for the purpose intended. The latter is especially true of certain essential oils, which otherwise. would be entirely suitable.

Aqueous solutions of the alkali metal sulfonated oils employed by us in the relatively small amounts stated interfere in no way with the setting or coagulating of the viscose, nor is there any objectionable effectproduced on the filaments formed by reasonof the introduction into the viscose solution before spinning of the alkali metal salts-of the non-mineral sulfonated acids as disclosed in this application.

'We give the. following details as an example of carrying our invention into effect, with the understanding that the alkali metal and oil mentioned therein, and the quantities stated are given for illustrative purposes only, and may be varied Within comparatively wide limits from the quantities herein stated without departing from the essence and spirit of our invention.

A du Nouy surface tension meter was em; ployed by us. in connection with these re searches, the instrument having first been calibrated from toluene, nitrobenzene, ani line, carbon tetrachloride and dimethyl ketone (acetone). It was found that the surface tension of the untreated spinning viscose used as a control was 46A dynes per cm. at 20 (3., and when the temperature of spinning wasraised to 40 0., the filaments issuing from the the spinnerettes became uneven in diameter, and in some instances discontinuous. I

Two tenths of one percent of the sodium salt of a sulfonated castor oil was stirred into another portion of the same viscose solution, and it was found that the viscose flowed in a uniform continuous stream from a 20- hole jet even at a temperature as high as 55 C., this phenomenon is ascribed by us as due to a diminution in surface tension. When the surface tension was retaken it was found to be 38.0 dynes per cm. these figures being the surface tension against air. A sample containing 0.4% of sodium sulfonated castor oil was then tested under comparable conditions and gave practically the same result from which it follows in the example above given that the surface tension of viscose may be reduced about 18% by the addition of a small quantity of the sodium sulfonated castor oil as herein stated and that varying within small limits the amount of water soluble sulfonated oil used, does not materially affect the degree of surface tension reduction. By the use of sulfonated oils other than castor oil, and by the use of an alkali metal other than sodium to combine with the mixed sulfonated acids, we have obtained results greater or lesser than that above stated in the lowering of the surface tension of a sample of spinning viscose.

In the application of the results observed by us on a factory scale, the aqueous solution of alkali metal salt of the sulfonated non-mineral oil used, may be introduced at any suitable place in the process of manufacture before the properly ripened viscose is ready to be spun. We have'found one suitable place is to incorporate the sulfonated oil salt with the alkali solution used to thin or attenuatethe raw viscose before the aging process hascommenced, and to age in an otherwise normal manner to the index desired for spinnin purposes.

Our rocess is or the treatment of viscose made rom pulp containing wood cellulose and does not employ sodium oleate or other alkali metal oleate in solution as such.

What we claim is:-

1. In the/manufacture of viscose solution comprising dissolving the xanthated cellulose in an aqueous solution containing an alkaline metal sulfonated non-mineral oil in amount not to exceed one percent to reduce the surface tension of said viscose solution before precipitation, then forcing said solution through orifices into a precipitating bath, and treating the coagulated filaments thus formed by ways now known,-substantially as herein set forth.

2. In the manufacture of viscose solution from cellulosic pul comprising dissolving the xanthated cellulbsein an aqueous solution containing not to exceed one percent of the alkali metal salt of a sulfonated veg etable oil to reduce the surface tension of sald viscose solution, then forcing the same through orifices into a precipitating or coagulating solution, and treatment of the precipitated viscose by ways now known substantially as setforth herein.

3. In the manufacture of viscose solution from pulp containing a proportion of wood cellulose, adding thereto an aqueous solution containing the alkali metal salt of a sulfonated castor oil in amounts of about 0.2% without adversely effecting the physical properties of said viscose solution for spinning purposes, then forcing said solution through orifices into a setting medium and treating the coagulated viscose by ways now known, as set forth herein.

4. In the manufacture of viscose solution from pulp containing a proportion of wood cellulose, the step comprising dissolving or thinning the xanthated collulose in an aqueous solution containing-the alkali metal salt of a sulfonated oil in amounts of about 0.2% to reduce the surface tension of said viscose solution for spinning purposes, then forcing said solution through orifices into a setting medium and treating the coagulated viscose by ways now known, as set forth herein.

5. In the manufacture of viscose filaments, the introduction into the viscose before the setting of the filaments of the same, of a relatively small amount of an aqueous solution of the alkali metal salt of asulfonated nonmineral oil, as herein described.

6. In the manufacture of viscose filaments, the lowering of the surface tension of the same by the introduction into the viscose be-' foresetting of a small amount of water-soluble sulfonated oil, as set forth herein.

7 In the process for reduction of surface tension in fi aments made from viscose solution by means of the sodium salt of a sulfonated oil dissolved in water or dilute alkali, the step which consists in adding the water-soluble sulfonated oil to the viscose in the stage of viscose manufacture in which the raw viscose is thinned with sodium hydroxide solution preparatory to submitting said viscose to the aging process, then fore: ing the aged viscose through orifices into a coagulating medium by ways now known,

1 substantially as set forth herein.

8. In a process for the manufacture of viscose filaments and films, the use of viscose prepared from pulp containing a propor- -tion of wood cellulose and containing approximately two-tenths of one percent of a water-soluble alkali metal salt of sulfonat ed castor oil to diminish the surface tension of the viscose filaments produced therefrom, said viscose containing thewater-soluble sulfonated oil being then forced through orifices of suitable size into a viscose coagunot to exceed one percent of the alkali metal lating solution, and then treated by ways salt of a sulfonated castor oil, afterwards 1" now known, substantially as set forth herein. projecting the ripened viscose through ori- 9. In the manufacture of viscose from fices into a coagulating bath and treatment 5 pulp containing a roportion of wood celluof the filaments thus formed in ways now lose, the step of re ucing the surface tension known, as herein set forth. of the solution by the addition to the vis- FRED. O. NIEDERHAUSER. cose solution before spinning, of an amount HAYDEN B. KLINE. 

